Abstract

MIA (Melanoma Inhibitory Activity) is a protein secreted from human melanoma cell lines which was cloned recently (Blesch et al. 1994). MIA is expressed only in and secreted from malignant melanomas and chondrocytes (Bosserhoff et al. 1997, 1999). As MIA expression in chondrocytes is dependent on the differentiation status of the cells, it was also named CD-RAP (cartilage-derived retinoic acid-sensitive protein). Recent evidence indicates an important role in tumour progression and metastasis, as MIA mediates detachment of melanoma cells from extracellular matrix molecules such as fibronectin (Stoll et al. 2001). MIA expression levels closely parallel the capability of melanoma cells to form metastases in syngeneic animals (Guba et al. 2000; Bosserhoff et al. 2001). Further, increased MIA serum levels have been used as a reliable and clinically useful marker to detect and monitor metastatic disease in patients with malignant melanomas (Bosserhoff et al. 1997).